The present disclosure relates to gas turbine engines. More particularly, the present disclosure relates to a platform of a vane and/or blade for a gas turbine engine.
A typical gas turbine engine includes a compressor section, a combustor section, and a turbine section fluidly connected along a main gas flow path. A gas (air) enters the main gas flow path, is pressurized in the compressor section and mixed with fuel in the combustor section. The mixture of gas and fuel is ignited in the combustor section to generate hot combustion gases. The turbine section is disposed downstream of the combustor section to receive the hot combustion gases. The turbine section extracts energy from the combustion gases to power the compressor. In turbofan aircraft applications, the turbine section also powers a fan. In marine or industrial applications, the turbine section powers an external drive shaft.
In an axial flow gas turbine engine, the turbine section and the compressor section are divided into stages, each stage is typically comprised of a plurality circumferentially arranged vane or blade structures. The blades are mounted to one or more hubs capable of rotation about an engine axis and the vanes are stator components that are mounted to structures such as the engine casing.
The blades and vanes include an airfoil and one or more platforms, also called endwalls. In most cases, the platforms are arranged adjacent each other to partially define a radially inner boundary of the annular main gas flow path for the gas turbine engine. The airfoils span across the main gas flow path so that the airfoil tips are in close proximity to a non-rotatable casing (in the case of rotor blades) or connect to a radially outer platform that defines a radially outer boundary of the annular main gas flow path.
During engine operation, gas (air and/or combustion gases) flows through the main gas flow path. Near the endwalls, the gas flow is dominated by a vortical flow structure known as a horseshoe vortex. The vortex forms as a result of the endwall boundary layer, which separates from the endwall as the fluid approaches the leading edges of the airfoils. The separated gas reorganizes into the horseshoe vortex. There is a high loss of efficiency associated with the vortex. The loss, commonly referred to as “secondary” or “endwall” loss, is responsible for significant efficiency loss in a row of airfoils.